This invention relates to the lining of pipelines and passageways using soft flexible lining tubes which are applied to the pipeline or passageway surface using fluid pressure, said lining tubes either comprising a layer such as a fibrous layer which is impregnated with a curable synthetic resin, or including an adhesive whereby the lining tube is bonded to the pipeline or passageway surface. In the case where the lining tube embodies a curable synthetic resin, the resin is cured while the lining tube lines the surface and upon such curing the tube in fact becomes a hard free-standing pipe of the pipeline or passageway surface. Where the flexible lining tube is bonded to the pipeline or passageway surface the fluid pressure is removed after bonding has been completed.
Various soft lining tube methods are known and are practiced, and in the most commonly practiced method the flexible lining tube is made up of at least one fibrous layer which is impregnated with a curable synthetic resin, and the tube is inverted into and along the pipeline or passageway using fluid pressure to apply the lining tube to the pipeline or passageway surface. In another method, a similarly impregnated lining tube is pulled into the pipeline or passageway, and then an inflation tube is everted into the lining tube, thereafter to be inflated to press the lining tube against the pipeline or passageway surface.
The present invention is concerned with a soft lining tube method wherein the pipeline or passageway is at the time actively conveying its normal contents, and with means for making unnecessary the interruption or external diversion of the liquid which normally passes through the pipeline or passageway when the pipeline or passageway is performing its normal function.
It will be understood that the soft lining methods are used extensively in the lining of sewer pipes or effluent pipes, and the handling of the sewage or effluent, hereinafter called the effluent in the interests of simplicity, while the lining operation is performed can cause difficulties and disadvantages. In the past, the effluent has usually been bypass pumped when the lining operation is taking place over a section of the pipeline or passageway, the effluent being pumped through a tube which is taken to ground level, and the tube returns the effluent to the pipeline or passageway at a position downstream of the section being lined. This technique is relatively satisfactory when relatively small diameter bypass pumping pipes, i.e. of the order of 4-6" diameter, are involved, because the said relatively small diameter pipes are easy to handle, and can be easily positioned and raised and lowered at ground level so as not to interfere with the general equipment used for the lining operation and traffic flow. However, when larger effluent flows are involved requiring the use of larger diameter bypass pipes, i.e. of the order of 12", then not only is considerably more expense involved in providing such a bypass pumping operation, but the handling of such a large diameter pipe at the lining site at ground level creates considerable difficulty. Furthermore, the fraction of the cost of the contract attributable to providing the bypass pumping at ground level increases sharply with the increasing bypass pipe diameter. Also, the bypassing of large diameter sewers can be difficult and risky and interfere to a greater extent with traffic flow in the vicinity.
In accordance with the present invention a bypass conduit extends through the lining tube before it has been fixed in place, so that effluent can flow through that conduit, preferably by pumping, while the steps necessary to secure the lining in place are carried out. The bypass conduit can readily be put into place by being appropriately connected to the lining tube as it is inserted, with an end of the bypass conduit projecting through the remote end of the lining tube after it has been inserted.
Preferably, the method involves connecting a T-junction to a pump which pumps the effluent initially along a discharge conduit lying in the pipeline or passageway, and over which the lining tube is applied, and from the other leg of the T the effluent can be pumped upwardly to ground level and then through the end of the bypass conduit which is inside the lining tube, the discharge conduit eventually being sacrificed when the lining operation has been completed.
The method may be used with the lining method wherein the impregnated flexible lining tube is everted into the pipeline or passageway to line same, or the alternative method wherein the lining tube is pulled into position. The method is also usable in those cases where a flexible lining tube having an adhesive on the inner surface thereof is everted into the pipeline or passageway to be bonded or adhered to the pipeline or passageway surface, as opposed to the formation of a rigid free-standing pipe which results when a thick fibrous material flexible lining tube is impregnated with a curable resin and is shaped to the pipeline or passageway surface and then the resin is cured.